1. Field of the Invention
The present invention generally relates to dynamic and fair resource allocation algorithm for OFDM systems.
2. Description of the Prior Art
Orthogonal Frequency-Division Multiplexing (OFDM) for multiple users has become a crucial scheme for the next-generation wireless communication. One of the characteristics for OFDM is that all the sub-carriers carrying data are orthogonal to each other. If the channel-state information (CSI) can be known perfectly, sub-carriers carrying data bits can achieve the best efficiency while maintaining fairness. A variety of methods have thus far been proposed to address these issues.
One method has been proposed by D. Kivanc, G. Li and H. Liu, titled “Computationally efficient bandwidth allocation and power control for OFDMA,” IEEE Trans. Wireless commun., vol. 2, pp. 1150-1158, November 2003, which allocates a suitable amount of sub-carriers to each user, and then decides which sub-carrier is to be allocated to a specific user. Such technique is computationally efficient, but very power consuming. In addition, if the overall bandwidth cannot satisfy all users, then users demanding lower data rates are sacrificed in order for the rest to continue. In terms of QoS, this technique is not fair.
In addition, a publication authored by T.-D. Nguyen and Y. Han, titled “A dynamic channel assignment algorithm for OFDMA systems,” in Proc. IEEE Veh. Technol. Conf.k September 2006 pp. 1-5, has proposed a dynamic channel assignment algorithm that makes a compromise between system output and fairness. However, this is based on the assumption that the allocation of the sub-carriers are of equal power distribution. This is unfavorable in terms of power consideration. Therefore, there is a need for a method that achieves better and fairer resource allocation while reducing transmission power.